1. Field of the Invention
This invention relates to a two-cycle engine system, more particularly a two-cycle engine system of the crankcase precompression type in which a first engine, a second engine, and a combustion chamber having an ignition plug therein are provided.
2. Prior Art
It has been known that the amount of harmful components in exhaust gases from an internal combustion engine can be reduced by stratifying two types of air-fuel mixtures, rich and lean, inside the combustion chamber, and igniting the rich mixture, flames of which propagates through the lean mixture.
Regarding four-cycle engines, the prior art discloses torch ignition internal combustion system and modifications thereof which include an auxiliary chamber having an ignition plug. In such systems a nozzle may be employed for supplying a rich mixture in an auxiliary ignition chamber to avoid ignition failures. The flames of the rich mixture in the auxiliary chamber thus ignited burst into the main combustion chamber and fire the lean mixture therein. The improvements of such prior art substantially exist in the ignition process employing an auxiliary chamber (or auxiliary ignition chamber) as an efficient torch ignition device. Accordingly, a fuel injection nozzle is used to supply the rich mixture and the volume of the auxiliary chamber is small in comparison with the main combustion chamber. In fact it can be generally observed that the nozzle to inject the fuel does not guarantee a sufficient effect in the atomization and vaporization of the fuel in the auxiliary chamber, which causes failures in igniting and firing the fuel. Moreover, the construction of such a device to supply the fuel is so complicated that it requires a very high precision in manufacturing and it may lead to possible mechanical difficulties. It should be further noted that in the case of a two-cycle engine of the crankcase precompression type, the burnt gases must be scavenged with the new mixture supplied, and the unburnt fuel may blow by through the exhaust port together with the burnt gases in order to obtain a sufficient scavenge performance. Thus, the prior art devices cannot be applied to a two-cycle engine.
With respect to a tow-cycle engine, other prior art teaches that an ignition chamber with a spheroidal structure and a passage to supply a rich mixture into the ignition chamber may advantageously be employed to attain an improved ignition and combustion by inducing a toroidal flow of the rich mixture in the chamber. In accordance with this system a certain extra time elapses in the combustion stroke because of the facts that the ignition process is effected in the toroidal flow of the rich mixture prior to the main combustion and that the majority of the fuel in the combustion chamber is the lean mixture which gives a relatively slower burning velocity. Accordingly, there remain some drawbacks unsolved such as the reduction of the thermal efficiency and of the speed of revolutions causing less power and overheating.
This invention solves those problems which the devices disclosed by the prior art have failed to resolve. The combination of a first engine, a second engine and a combustion chamber has enabled the minimization of the drawbacks described above in a most compact manner.